Chemical insecticides remain as the most important agents for the control of vector-borne diseases such as malaria, dengue, filariasis etc. Countless deaths from these diseases have been spared since the introduction of the first synthetic insecticide, DDT in the 1940's. Prolonged use of insecticides has however, induced the development of resistance in the vectors, primarily insects, that carry such diseases, which renders them less effective in combating the vectors and thus the diseases that they spread. Resistance detection is mainly based on the World Health Organisation (WHO) standard test procedures which, among other things, are not user-friendly, use test kits of short shelf life and need skilled manpower to conduct the tests and interpret the test results. As a result, very often little is known of the susceptibility status of many insect vectors, which tends to affect the outcomes of control programmes.
The development of rapid field test kits would be a major breakthrough in the control of vector-borne diseases.
In general, the biochemical basis of resistance is due to 3 mechanisms:                1) increased level of non-specific esterases targeted against organophosphates and carbamates;        2) elevated activity of mixed-function oxidases against pyrethroids; and        3) non-susceptability of acetylcholine esterase against organophosphates and carbamates.        